Historical Note

Former Section R9-21-101 repealed, new Section R9-21-101 adopted effective January 29, 1980 (Supp. 80-1). Amended effective April 17, 1984 (Supp. 84-2). Amended effective January 7, 1985 (Supp. 85-1). Amended by adding subsection (C) effective August 12, 1986 (Supp. 86-4). Former Section R9-21-101 renumbered without change as Section R18-11-101 (Supp. 87-3). Former Section R18-11-101 repealed, new Section R18-11-101 adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Deleted first definition to R18-11-101(32) "Navigable Water", previously printed in error
(Supp. 96-3). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1). Amended by final rulemaking at 9 A.A.R. 716, effective April 8, 2003 (Supp. 03-1).

R18-11-102. Applicability

A. The water quality standards prescribed in this Article apply to surface waters.

B. The water quality standards prescribed in this Article do not apply to the following:

1. A waste treatment system, including an impoundment, pond, lagoon, or constructed wetland that is a part of the waste treatment system.

2. A man-made surface impoundment and associated ditches and conveyances used in the extraction, beneficiation, or processing of metallic ores, including a pit, pregnant leach solution pond, raffinate pond, tailing impoundment, decant pond, pond or a sump in a mine pit associated with dewatering activity, pond holding water that has come into contact with a process or product and that is being held for recycling, spill or upset catchment pond, or pond used for onsite remediation, that is not a surface water or is located in an area that once was a surface water but no longer remains a surface water because it has been and remains legally converted.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-103. Repealed

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Repealed effective April 24, 1996 (Supp. 96-2).

R18-11-104. Designated Uses

A. The Director shall adopt or remove a designated use or subcategory of a designated use by rule.

B. Designated uses of a surface water may include full-body contact, partial-body contact, domestic water source, fish consumption, aquatic and wildlife (cold water), aquatic and wildlife (warm water), aquatic and wildlife (ephemeral), aquatic and wildlife (effluent-dependent water), agricultural irrigation, and agricultural livestock watering. The designated uses for specific surface waters are listed in Appendix B of this Article.

C. Numeric water quality criteria to maintain and protect water quality for the designated uses are prescribed in Appendix A, R18-11-109, R18-11-110, and R18-11-112. Narrative water quality standards to protect all surface waters are prescribed in R18-11-108.

D. If a surface water has more than one designated use listed in Appendix B, the most stringent water quality criterion applies.

E. The Director shall revise the designated uses of a surface water if water quality improvements result in a level of water quality that permits a use that is not currently listed as a designated use in Appendix B.

F. In designating uses of a surface water and in establishing water quality criteria to protect the designated uses, the Director shall take into consideration the applicable water quality standards for downstream surface waters and shall ensure that the water quality standards that are established for an upstream surface water also provide for the attainment and maintenance of the water quality standards of downstream surface waters.

G. A use attainability analysis shall be conducted prior to removal of a designated use or adoption of a subcategory of a designated use that requires less stringent water quality criteria.

H. The Director may remove a designated use or adopt a subcategory of a designated use that requires less stringent water quality criteria, provided the designated use is not an existing use and it is demonstrated through a use attainability analysis that attaining the designated use is not feasible for any of the following reasons:

1. A naturally-occurring pollutant concentration prevents the attainment of the use;

2. A natural, ephemeral, intermittent, or low-flow condition or water level prevents the attainment of the use;

3. A human-caused condition or source of pollution prevents the attainment of the use and cannot be remedied or would cause more environmental damage to correct than to leave in place;

4. A dam, diversion, or other type of hydrologic modification precludes the attainment of the use, and it is not feasible to restore the surface water to its original condition or to operate the modification in a way that would result in attainment of the use;

5. A physical condition related to the natural features of the surface water, such as the lack of a proper substrate, cover, flow, depth, pools, riffles, and the like, unrelated to water quality, precludes attainment of an aquatic life designated use; or

6. Controls more stringent than those required by § 301 (b) and § 306 of the Clean Water Act [33 U.S.C. § 1311 and § 1316] are necessary to attain the use and implementation of the controls would result in substantial and widespread economic and social impact.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-105. Tributaries; Designated Uses

The following water quality standards apply to a surface water that is not listed in Appendix B but that is a tributary to a listed surface water.

1. The aquatic and wildlife (ephemeral) and partial-body contact standards apply to an unlisted tributary that is an ephemeral water.

2. The aquatic and wildlife (cold water), full-body contact, and fish consumption standards apply to an unlisted tributary that is a perennial or intermittent surface water and is above 5000 feet in elevation.

3. The aquatic and wildlife (warm water), full-body contact, and fish consumption standards apply to an unlisted tributary that is a perennial or intermittent surface water and is below 5000 feet in elevation.

Historical Note

Adopted effective April 24, 1996 (Supp. 96-2). Section heading amended per instructions of the Department of Environmental Quality, August 9, 1996 (Supp. 96-3). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-106. Net Ecological Benefit

A. The Director may, by rule, modify a water quality standard on the ground that there is a net ecological benefit associated with the discharge of effluent to support or create a riparian and aquatic habitat in an area where water resources are limited. The Director may modify a water quality standard for a pollutant if it is demonstrated that:

1. The discharge of effluent creates or supports an ecologically valuable aquatic, wetland, or riparian ecosystem in an area where these resources are limited;

2. The ecological benefits associated with the discharge of effluent under a modified water quality standard exceed the environmental costs associated with the elimination of the discharge of effluent;

3. The cost of treatment to achieve compliance with a water quality standard is so high that it is more cost effective to eliminate the discharge of effluent to the surface water. The discharger shall demonstrate that it is feasible to eliminate the discharge of effluent that creates or supports the ecologically valuable aquatic, wetland, or riparian ecosystem and that a plan to eliminate the discharge is under active consideration;

4. The discharge of effluent to the surface water will not cause or contribute to a violation of a water quality standard that has been established for a downstream surface water;

5. All practicable point source discharge control programs, including local pretreatment, waste minimization, and source reduction programs are implemented; and

6. The discharge of effluent does not produce or contribute to the concentration of a pollutant in the tissues of aquatic organisms or wildlife that is likely to be harmful to humans or wildlife through food chain concentration.

B. The Director shall not modify a water quality criterion for a pollutant to be less stringent than a technology-based effluent limitation that applies to the discharge of that effluent. The discharge of effluent shall, at a minimum, comply with applicable technology-based effluent limitations.

Historical Note

Adopted effective April 24, 1996 (Supp. 96-2). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-107. Antidegradation

A. The Director shall determine whether there is degradation of water quality in a surface water on a pollutant-by-pollutant basis.

B. Tier 1: The level of water quality necessary to protect existing uses shall be maintained and protected. No degradation of existing water quality is permitted in a surface water where the existing water quality does not meet the applicable water quality standard.

C. Tier 2: Where existing water quality in a surface water is better than the applicable water quality standard, the existing water quality shall be maintained and protected. The Director may allow limited degradation of existing water quality in the surface water, provided that the Department holds a public hearing on whether degradation should be allowed under the general public hearing procedures prescribed at R18-1-401 and R18-1-402 and the Director makes all of the following findings:

1. The level of water quality necessary to protect existing uses is fully protected. Water quality shall not be lowered to a level that does not comply with applicable water quality standards.

2. The highest statutory and regulatory requirements for new and existing point sources are achieved.

3. All cost-effective and reasonable best management practices for nonpoint source pollution control are implemented.

4. Allowing lower water quality is necessary to accommodate important economic or social development in the area where the surface water is located.

D. Tier 3: Existing water quality shall be maintained and protected in a surface water that is classified as a unique water under R18-11-112. The Director shall not allow limited degradation of a unique water under subsection (C).

E. The Department shall implement this Section in a manner consistent with § 316 of the Clean Water Act [33 U.S.C. § 1326] if a potential water quality impairment associated with a thermal discharge is involved.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-108. Narrative Water Quality Standards

A. A surface water shall be free from pollutants in amounts or combinations that:

1. Settle to form bottom deposits that inhibit or prohibit the habitation, growth, or propagation of aquatic life;

2. Cause objectionable odor in the area in which the surface water is located;

3. Cause off-taste or odor in drinking water;

4. Cause off-flavor in aquatic organisms;

5. Are toxic to humans, animals, plants, or other organisms;

6. Cause the growth of algae or aquatic plants that inhibit or prohibit the habitation, growth, or propagation of other aquatic life or that impair recreational uses;

7. Cause or contribute to a violation of an aquifer water quality standard prescribed in R18-11-405 or R18-11-406; or

8. Change the color of the surface water from natural background levels of color.

B. A surface water shall be free from oil, grease, and other pollutants that float as debris, foam, or scum; or that cause a film or iridescent appearance on the surface of the water; or that cause a deposit on a shoreline, bank, or aquatic vegetation. The discharge of lubricating oil or gasoline associated with the normal operation of a recreational watercraft is not a violation of this narrative standard.

C. A discharge of suspended solids to a surface water shall not be in quantities or concentrations that either interfere with the treatment processes at the nearest downstream potable water treatment plant or substantially increase the cost of handling solids produced at the nearest downstream potable water treatment plant.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-109. Numeric Water Quality Standards

A. The following water quality standards for Escherichia coli (E. coli), expressed in colony forming units per 100 milliliters of water (cfu / 100 ml), shall not be exceeded:

E. coli FBC PBC

Geometric mean (four-sample minimum) 126 126

Single sample maximum 235 576

B. The following water quality standards for pH, expressed in standard units, shall not be violated:

pH DWS FBC, PBC, A&W ¹ AgI AgL

Maximum 9.0 9.0 9.0 9.0

Minimum 5.0 6.5 4.5 6.5

Maximum change

due to discharge NNS 0.5 NNS NNS

C. The following maximum allowable increase in ambient water temperature, expressed in degrees Celsius, shall not be exceeded:

Temperature A&Ww, A&Wedw A&Wc

Maximum increase

due to a thermal discharge ^2,3 3.0 1.0

D. The following water quality standard for suspended sediment concentration, expressed as a geometric mean (four-sample minimum) shall not be exceeded. The standard applies to a surface water that is at or near base flow and does not apply to a surface water during or soon after a precipitation event:

A&Wc, A&Ww

80 mg / L

E. The following are the water quality standards for dissolved oxygen, expressed in milligrams per liter (mg/L). The dissolved oxygen concentration in a surface water shall not fall below the following minimum concentrations:

1. Dissolved oxygen A&Ww A&Wc

Single sample minimum ⁴ 6.0 7.0

2. Dissolved oxygen in effluent-dependent waters

(single sample minimum): A&W edw

Three hours after sunrise to sunset 3.0

Sunset to three hours after sunrise 1.0

3. A surface water is in compliance with the water quality standard for dissolved oxygen if the percent saturation of dissolved oxygen is equal to or greater than 90%.

F. The following water quality standards for total phosphorus and total nitrogen, expressed in milligrams per liter (mg/L), shall not be exceeded:

G. The following water quality standards for radiochemicals shall not be exceeded in surface waters with the domestic water source designated use:

1. The concentration of gross alpha particle activity, including radium-226, but excluding radon and uranium, shall not exceed 15 picocuries per liter of water.

2. The concentration of combined radium-226 and radium-228 shall not exceed five picocuries per liter of water.

3. The concentration of strontium-90 shall not exceed 8 eight picocuries per liter of water.

4. The concentration of tritium shall not exceed 20,000 picocuries per liter of water.

5. The average annual concentration of beta particle activity and photon emitters from manmade radionuclides shall not produce an annual dose equivalent to the total body or any internal organ greater than four millirems per year.

Footnotes:

¹ Includes A&Wc, A&Ww, A&Wedw, and A&We.

² Does not apply to Cholla Lake.

³ Does not apply to a wastewater treatment plant discharge to a dry watercourse that creates an effluent-dependent water or to a stormwater discharge.

⁴ The dissolved oxygen water quality standard for a lake shall apply below the surface but not at a depth greater than one meter.

⁵ Means the annual mean of representative composite samples taken from the surface and at two and five meter depths.

⁶ Means the maximum for any set of representative composite samples taken from the surface and at two and five meter depths.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-110. Salinity Standards for the Colorado River

A. The flow-weighted average annual salinity in the lower main stem of the Colorado River shall be maintained at or below the following concentrations:

Location Total Dissolved Solids

Below Hoover Dam 723 mg/L

Below Parker Dam 747 mg/L

At Imperial Dam 879 mg/L

B. To preserve the basin-wide approach to salinity control developed by the Colorado River Basin states and to ensure compliance with the numeric criteria for salinity in subsection (A), the Department adopts the plan of implementation contained in the "1999 Review, Water Quality Standards for Salinity, Colorado River System," Colorado River Basin Salinity Control Forum, 106 West 500 South, Suite 101, Bountiful, Utah 84010-6232 (June, 1999), which is incorporated by reference and on file with the Office of the Secretary of State and the Department. This incorporation by reference contains no future editions or amendments.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-111. Analytical Methods

A. A person conducting an analysis of a sample taken to determine compliance with a water quality standard shall use an approved analytical method prescribed in 9 A.A.C. 14, Article 6, or an alternative analytical method that is approved by the Director of the Arizona Department of Health Services under R9-16-610(B).

B. A test result from a sample taken to determine compliance with a water quality standard is valid only if the sample is analyzed by a laboratory that is licensed by the Arizona Department of Health Services for the analysis performed.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-112. Unique Waters

A. The Director shall classify a surface water as a unique water by rule. The Director shall consider nominations to classify a surface water as a unique water during the triennial review of water quality standards for surface waters.

B. The Director may adopt, by rule, site-specific water quality standards to maintain and protect existing water quality in a unique water.

C. Any person may nominate a surface water for classification as a unique water by filing a nomination with the Department. The nomination to classify a surface water as a unique water shall include:

1. A map and a description of the surface water;

2. A written statement in support of the nomination, including specific reference to the applicable criteria for unique water classification prescribed in subsection (D);

3. Supporting evidence demonstrating that the applicable unique water criteria prescribed in subsection (D) are met; and

4. Available water quality data relevant to establishing the baseline water quality of the proposed unique water.

D. The Director may classify a surface water as a unique water upon finding that the surface water is an outstanding state resource water based upon the following criteria:

1. The surface water is a perennial water;

2. The surface water is in a free-flowing condition. For purposes of this subsection, "in a free-flowing condition" means that a surface water does not have an impoundment, diversion, channelization, rip-rapping or other bank armor, or another hydrological modification within the reach nominated for unique water classification;

3. The surface water has good water quality. For purposes of this subsection, "good water quality" means that the surface water has water quality that meets or exceeds applicable surface water quality standards. A surface water that is listed as impaired under § 303(d) of the Clean Water Act (33 U.S.C. § 1313) is ineligible for unique waters classification; and

4. The surface water meets one or both of the following conditions:

a. The surface water is of exceptional recreational or ecological significance because of its unique attributes, including but not limited to, attributes related to the geology, flora, fauna, water quality, aesthetic values, or the wilderness characteristics of the surface water.

b. Threatened or endangered species are known to be associated with the surface water and the existing water quality is essential to the maintenance and propagation of a threatened or endangered species or the surface water provides critical habitat for a threatened or endangered species. Endangered or threatened species are identified in Endangered and Threatened Wildlife and Plants, 50 CFR § 17.11 and § 17.12 (revised as of October 1, 2000) which is incorporated by reference and on file with the Department and the Office of the Secretary of State. This incorporation by reference contains no future editions or amendments.

E. The following surface waters are classified as unique waters:

1. The West Fork of the Little Colorado River, above Government Springs;

2. Oak Creek, including the West Fork of Oak Creek;

3. Peoples Canyon Creek, tributary to the Santa Maria River;

4. Burro Creek, above its confluence with Boulder Creek;

5. Francis Creek, in Mohave and Yavapai counties;

6. Bonita Creek, tributary to the upper Gila River;

7. Cienega Creek, from confluence with Gardner Canyon and Spring Water Canyon at R18E T17S to USGS gaging station at 32°02'09" / 110°40'34", in Pima County;

8. Aravaipa Creek, from its confluence with Stowe Gulch to the downstream boundary of Aravaipa Canyon Wilderness Area;

9. Cave Creek and the South Fork of Cave Creek (Chircahua Mountains), from the headwaters to the Coronado National Forest boundary;

10. Buehman Canyon Creek, from its headwaters (Lat. 32°24'55.5" N, Long. 110°39'43.5"W) to approximately 9.8 miles downstream (Lat. 32°24'31.5" N, Long. 10°32'08" W);

11. Lee Valley Creek, from its headwaters to Lee Valley Reservoir;

12. Bear Wallow Creek, from its headwaters to the boundary of the San Carlos Indian Reservation;

13. North Fork of Bear Wallow Creek, from its headwaters to Bear Wallow Creek;

14. South Fork of Bear Wallow Creek, from its headwaters to Bear Wallow Creek;

15. Snake Creek, from its headwaters to its confluence with Black River;

17. Hay Creek, from its headwaters to its confluence with the West Fork of the Black River;

18. Stinky Creek, from the Fort Apache Indian Reservation boundary to its confluence with the West Fork of the Black River; and

19. KP Creek, from its headwaters to its confluence with the Blue River.

F. The Department shall hold at least one public meeting in the local area of a nominated unique water to solicit public comment on the nomination.

G. The Director may consider the following factors when making a decision whether to classify a nominated surface water as a unique water:

1. Whether there is the ability to manage the unique water and its watershed to maintain and protect existing water quality;

2. The social and economic impact of Tier 3 antidegradation protection;

3. The public comments in support or opposition to a unique waters classification;

4. The support or opposition of federal and state land management and natural resources agencies to a nomination;

5. Agency resource constraints;

6. The timing of the unique water nomination relative to the triennial review of surface water quality standards;

7. The consistency of a unique water classification with applicable water quality management plans (for example, § 208 water quality management plans); and

8. Whether the nominated surface water is located within a national or state park, national monument, national recreation area, wilderness area, riparian conservation area, area of critical environmental concern, or it has another special use designation (for example, Wild and Scenic River designation).

H. The following water quality standards apply to the listed unique waters. Water quality standards prescribed in this subsection supplement the water quality standards prescribed by this Article.

Abbreviations:

"(D)" means dissolved fraction

"(T)" means total recoverable

"NTUs" means nephelometric turbidity units

"mg / L" means milligrams per liter

"µg / L" means micrograms per liter

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Added "water quality standards" to R18-11-112, previously omitted in error (Supp. 96-3). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-113. Effluent-dependent Waters

A. The Director shall classify a surface water as an effluent-dependent water by rule.

B. The Director may adopt, by rule, site-specific water quality standards for an effluent-dependent water.

C. Any person may submit a petition for rule adoption requesting that the Director classify a surface water as an effluent-dependent water. The petition for rule adoption shall include:

1. A map and a description of the surface water,

2. Information that demonstrates that the surface water consists of discharges of treated wastewater, and

3. Information that demonstrates that the receiving water is an ephemeral water in the absence of the discharge of treated wastewater.

D. The following surface waters are classified as effluent-dependent waters:

1. In the Colorado River Main Stem Basin:

a. Bright Angel Wash from the South Rim Grand Canyon WWTP outfall to its confluence with Coconino Wash,

b. Cataract Creek from the Williams WWTP outfall to one kilometer downstream from the outfall,

c. Holy Moses Wash from the Kingman WWTP outfall to three kilometers downstream from the outfall, and

d. Transept Canyon from the North Rim Grand Canyon WWTP outfall to one kilometer downstream from the outfall.

2. In the Little Colorado River Basin:

a. Dry Lake,

b. Lake Humphreys,

c. Lower Walnut Canyon Lake,

d. Ned Lake,

e. Pintail Lake,

f. Telephone Lake,

g. Rio de Flag from the City of Flagstaff WWTP outfall to its confluence with San Francisco Wash, and

h. Whale Lake.

3. In the Middle Gila River Basin:

a. Unnamed wash from the Town of Prescott Valley WWTP outfall to its confluence with the Agua Fria River, and the Agua Fria River below its confluence with the unnamed wash receiving treated wastewater from the Prescott Valley WWTP to State Route 169;

b. Agua Fria river from the El Mirage WWTP outfall to two kilometers downstream from the outfall;

c. Gila River from the Florence WWTP outfall to Felix Road,

d. Gila River from its confluence with the Salt River to Gillespie Dam;

e. Queen Creek from the Town of Superior WWTP outfall to its confluence with Potts Canyon;

f. Unnamed wash from the Gila Bend WWTP outfall to its confluence with the Gila River;

g. Unnamed wash from the Luke AFB WWTP outfall to its confluence with the Agua Fria River; and

h. Unnamed wash from the Queen Valley WWTP outfall to its confluence with Queen Creek.

4. In the Rios de Mexico Basin:

a. Mule Gulch, from the Bisbee WWTP outfall to the Highway 80 bridge, and

b. Unnamed wash from the Bisbee-Douglas International Airport WWTP outfall to Whitewater Draw.

5. In the Salt River Basin:

a. Unnamed wash from the Globe WWTP outfall to its confluence with Pinal Creek and Pinal Creek from its confluence with the unnamed wash to Radium, and

b. Salt River from the 23rd Avenue WWTP outfall to its confluence with the Gila River.

6. In the San Pedro River Basin:

a. Unnamed wash from the Mt. Lemmon WWTP outfall to 0.25 kilometers downstream, and

b. Walnut Gulch from the Tombstone WWTP outfall to its confluence with Tombstone Gulch.

7. In the Santa Cruz Basin:

a. Santa Cruz River from the Nogales International WWTP outfall to Tubac Bridge,

b. Santa Cruz River from the Roger Road WWTP outfall to Baumgartner Road crossing,

c. Unnamed wash from the Oracle WWTP outfall to five kilometers downstream, and

d. Sonoita Creek from the Town of Patagonia WWTP outfall to 750 feet downstream.

8. In the Upper Gila River Basin:

a. Bennett Wash from the Arizona Department of Corrections-Safford WWTP outfall to the Gila River. and

b. Unnamed wash from the Arizona Department of Corrections-Globe WWTP outfall to the boundary of the San Carlos Indian Reservation.

9. In the Verde River Basin:

a. American Gulch from the Northern Gila County Sanitary District WWTP outfall to the East Verde River,

b. Bitter Creek from the Jerome WWTP outfall to 2.5 kilometers downstream from the outfall, and

c. Jacks Canyon Wash from the Big Park WWTP outfall to its confluence with Dry Beaver Creek.

10. In the Willcox Playa Basin: Lake Cochise

E. The NPDES permit issuing authority shall use the water quality standards that apply to an effluent-dependent water to derive discharge limitations for a point source discharge from a wastewater treatment plant to an ephemeral water that changes that ephemeral water into an effluent-dependent water.

F. The site-specific standard of 36 µg / L for dissolved copper for the aquatic and wildlife (effluent-dependent water) designated use applies to the Rio de Flag from the City of Flagstaff WWTP outfall to its confluence with the San Francisco Wash.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective December 18, 1992 (Supp. 92-4). Amended effective April 24, 1996 (Supp. 96-2). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-114. Mixing Zones

A. The Director may establish a mixing zone for a point source discharge to a surface water as a condition of a NPDES permit. Mixing zones are prohibited in ephemeral waters or where there is no water for dilution.

B. The owner or operator of a point source seeking the establishment of a mixing zone shall submit a mixing zone application to the Department on a standard form that is available from the Department. The application shall include:

1. Identification of the pollutant for which the mixing zone is requested;

2. A proposed outfall design;

3. A definition of the boundary of the proposed mixing zone. For purposes of this subsection, the boundary of a mixing zone means the location where the concentration of treated wastewater across a transect of the surface water differs by less than 5%; and

4. A complete and detailed description of the existing physical, biological, and chemical conditions of the receiving water and the predicted impact of the proposed mixing zone on those conditions.

C. The Department shall review the application for a mixing zone to determine whether the application is complete. If the application is incomplete, the Department shall identify in writing the additional information that must be submitted to the Department to complete the mixing zone application.

D. The Director shall consider the following factors when deciding whether to grant or deny a request for a mixing zone:

1. The assimilative capacity of the receiving water;

2. The likelihood of adverse human health effects;

3. The location of drinking water plant intakes and public swimming areas;

4. The predicted exposure of biota and the likelihood that resident biota will be adversely affected;

5. Bioaccumulation and bioconcentration;

6. Whether there will be acute toxicity in the mixing zone, and, if so, the size of the area of acute toxicity;

7. The known or predicted safe exposure levels for the pollutant of concern;

8. The size of the mixing zone;

9. The location of the mixing zone relative to biologically sensitive areas in the surface water;

10. The concentration gradient of the pollutant within the mixing zone;

11. Sediment deposition;

12. The potential for attracting aquatic life to the mixing zone; and

13. The cumulative impacts of other mixing zones and other discharges to the surface water.

E. The Director shall deny the request to establish a mixing zone if water quality standards outside the boundaries of the proposed mixing zone will be violated. The denial of a request for a mixing zone shall be in writing and shall state the reason for the denial. If the Director determines that a mixing zone should be established, the Director shall establish the mixing zone as a condition of a NPDES permit. The Director may include mixing zone conditions in the NPDES permit that the Director deems necessary to protect human health and the designated uses of the surface water.

F. Any person who is adversely affected by the Director's decision to grant or deny a request for a mixing zone may appeal the decision to an administrative law judge under A.R.S. § 49-321 and A.R.S. § 41-1092 et seq.

G. The Department shall reevaluate a mixing zone upon issuance, reissuance, or modification of the National Pollutant Discharge Elimination System permit for the point source or a modification of the outfall structure.

H. The length of a mixing zone shall not exceed 500 meters in a stream. The total horizontal area allocated to all mixing zones on a lake shall not exceed 10% of the surface area of the lake. Adjacent mixing zones in a lake shall be no closer than the greatest horizontal dimension of any individual mixing zone.

I. A mixing zone shall provide for a zone of passage of not less than 50% of the cross-sectional area of a river or stream.

J. The discharge outfall shall be designed to maximize initial dilution of the treated wastewater in a surface water.

K. A mixing zone is prohibited for the following persistent, bioaccumulative pollutants:

1. Chlordane,

2. DDT and its metabolites (DDD and DDE),

3. Dieldrin,

4. Dioxin,

5. Endrin,

6. Endrin aldehyde,

7. Heptachlor,

8. Heptachlor epoxide,

9. Lindane,

10. Mercury,

11. PCBs, and

12. Toxaphene.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-115. Repealed

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Section repealed by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-116. Resource management agencies

Nothing in this Article shall be construed to prohibit fisheries management activities by the Arizona Game and Fish Department or the U.S. Fish and Wildlife Service. This provision does not exempt fish hatcheries from National Pollutant Discharge Elimination System permit requirements.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1).

R18-11-117. Canals and Municipal Park Lakes

A. Nothing in this Article shall be construed to prevent the routine physical or mechanical maintenance of canals, drains, and the municipal park lakes identified in Appendix B. Physical or mechanical maintenance includes dewatering, lining, dredging, and the physical, biological or chemical control of weeds and algae. Increases in turbidity that result from physical or mechanical maintenance activities are permitted in canals, drains, and the municipal park lakes identified in Appendix B.

B. The discharge of lubricating oil that is associated with the start-up of well pumps which discharge to canals is not a violation of R18-11-108(B).

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2).

R18-11-118. Dams and Flood Control Structures

A. Increases in turbidity that result from the routine physical or mechanical maintenance of a dam or flood control structure are not violations of this Article.

B. Nothing in this Article shall be construed to require the release of water from a dam or a flood control structure.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-119. Natural background

Where the concentration of a pollutant exceeds a water quality standard and the exceedance is not caused by human activity but is due solely to naturally-occurring conditions, the exceedance shall not be considered a violation of the water quality standard.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1).

R18-11-120. Enforcement

A. Any person who causes a violation of a water quality standard or any provision of this Article is subject to the enforcement provisions in A.R.S. Title 49, Chapter 2, Article 4.

B. The Department may establish a numeric water quality standard at a concentration that is below the practical quantitation limit. In such cases, the water quality standard is enforceable at the practical quantitation limit.

C. The Department shall determine compliance with acute aquatic and wildlife criteria from the analytical result of a grab sample. Compliance with chronic aquatic and wildlife criteria shall be determined from the geometric mean of the analytical results of the last four samples taken at least 24 hours apart.

D. A person is not subject to penalties for violation of a water quality standard provided that the person is in compliance with the provisions of a compliance schedule issued under R18-11-121.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-121. Schedules of Compliance

A. A schedule to bring an existing point source into compliance with a new or revised water quality standard may be established in a National Pollutant Discharge Elimination System permit for an existing point source. A compliance schedule for an existing point source, other than a storm water discharge, shall require compliance with a discharge limitation based upon a new or revised water quality standard no later than three years after the effective date of the National Pollutant Discharge Elimination System permit. For a schedule of compliance to be granted, the owner or operator of the existing point source shall demonstrate that all requirements under § 301(b) and § 306 of the Clean Water Act [33 U.S.C. § 1311(b) and § 1316] have been achieved and that the point source cannot comply with a discharge limitation based upon the new or revised water quality standard through the application of existing water pollution control technology, operational changes, or source reduction.

B. A schedule of compliance may be established in a National Pollutant Discharge Elimination System permit for a new point source. The first National Pollutant Discharge Elimination System permit issued to a new point source may contain a schedule of compliance only when necessary to allow a reasonable opportunity to attain compliance with a new or revised water quality standard that becomes effective after commencement of construction but less than three years before commencement of the discharge. For purposes of this subsection, commencement of construction means that the owner or operator of the point source has obtained the federal, state, and local approvals or permits necessary to begin physical construction of the point source and either:

1. Onsite physical construction has begun; or

2. The owner or operator has entered into a contract for physical construction of the point source and the contract cannot be cancelled or modified without substantial loss. For purposes of this subsection, "substantial loss" means in excess of 10% of the total cost incurred for physical construction.

C. A schedule of compliance may be established in a National Pollutant Discharge Elimination System permit for a recommencing point source discharge. The first National Pollutant Discharge Elimination System permit issued to a recommencing point source discharge may contain a schedule of compliance only when necessary to allow a reasonable opportunity to attain compliance with a new or revised water quality standard that becomes effective less than three years before recommencement of discharge.

D. A schedule to bring a point source discharge of storm water into compliance with a water quality standard may be established in a National Pollutant Discharge Elimination System permit. A compliance schedule for a storm water discharge shall require implementation of all reasonable and cost-effective best management practices to control the discharge of pollutants in storm water.

Historical Note

Adopted effective February 18, 1992 (Supp. 92-1). Amended effective April 24, 1996 (Supp. 96-2). Amended by final rulemaking at 8 A.A.R. 1264, effective March 8, 2002 (Supp. 02-1).

R18-11-122. Variances

A. The Director may grant a variance from a water quality standard for a point source discharge if the discharger demonstrates that treatment more advanced than that required to comply with technology-based effluent limitations is necessary to comply with the water quality standard and:

1. It is not technically feasible to achieve compliance within the next five years,

2. The cost of the treatment would result in substantial and widespread economic and social impact, or

3. Human-caused conditions or sources of pollution prevent attainment of the water quality standard and cannot be remedied within the next five years.

B. A variance may be granted only on a pollutant-specific basis. A point source discharge is required to comply with all other applicable water quality standards for which a variance is not granted.

C. A variance applies only to a specific point source discharge. The granting of a variance does not modify a water quality standard. Other point source dischargers to the surface water shall comply with applicable water quality standards, including any water quality standard for which a variance has been granted for a specific point source discharge.

D. A variance is for a fixed term not to exceed five years. Upon expiration of a variance, a point source discharger shall either comply with the water quality standard or apply for renewal of the variance. To renew a variance, the applicant shall demonstrate reasonable progress towards compliance with the water quality standard during the term of the variance.

E. The Department shall reevaluate a variance upon the issuance, reissuance, or modification of the National Pollutant Discharge Elimination System permit for the point source discharge.

F. A person who seeks a variance from a water quality standard shall submit a written request for a variance to the Department. A request for a variance shall include the following information:

1. Identification of the specific pollutant and water quality standard for which a variance is sought;

2. Identification of the receiving surface water;

3. For an existing point source discharge, a detailed description of the existing discharge control technologies that are used to achieve compliance with applicable water quality standards. For a new point source discharge, a detailed description of the proposed discharge control technologies that will be used to achieve compliance with applicable water quality standards;

4. Documentation that the existing or proposed discharge control technologies will comply with applicable technology-based effluent limitations and that more advanced treatment technology is necessary to achieve compliance with the water quality standard for which a variance is sought;

5. A detailed discussion of the reasons why compliance with the water quality standard cannot be achieved;

6. A detailed discussion of the discharge control technologies that are available for achieving compliance with the water quality standard for which a variance is sought;

7. Documentation of one of the following:

a. That it is not technically feasible to install and operate any of the available discharge control technologies to achieve compliance with the water quality standard for which a variance is sought,

b. That installation and operation of each of the available discharge technologies to achieve compliance with the water quality standard would result in substantial and widespread economic and social impact, or

c. That human-caused conditions or sources of pollution prevent the attainment of the water quality standard for which the variance is sought and it is not possible to remedy the conditions or sources of pollution within the next five years,

8. Documentation that the point source discharger has reduced, to the maximum extent practicable, the discharge of the pollutant for which a variance is sought through implementation of a local pretreatment, source reduction, or waste minimization program, and